How do i buy M rated content for my Xboxlive thing?

Ok! So i finally got Xbox live. I am 15 under in the profile. I want to buy content for my games such as dragon age origins and others. It says i can't on this profile. is there anyway to allow access to that or change my age settings?How do i buy M rated content for my Xboxlive thing?Your parents setup parental controls, so no, there is no way for you to do it yourself. But your dad/mom can give you access through their own Xbox Live login.